The present invention relates to a rock drilling machine especially for underground mining.
More particularly it relates to a rock drilling machine for underground mining which has a drilling carriage, a rotary drilling drive arranged on the drilling carriage displaceably by a displacing device and provided with a drive shaft, an adaptor fixedly connected with the drive shaft for joint rotation therewith and provided with a threaded end for form-locking receipt of drilling rods with a respective counter thread, and a clamping head which co-rotates with the drive shaft and is provided for force-transmitting receipt of outwardly smooth drilling rods.
Rock drilling machines of the above mentioned type are known in the art. One of such rock drilling machines is disclosed for example in the German document DE-AS 20 18 884. In the machine disclosed in this document the threaded end of the drive shaft is offset back relative to the clamping head for form-locking receipt of drilling rods. The threaded end of the drive shaft is engaged by the clamping heads at its both sides and therefore cannot be seen from the outside. Thereby the introduction of a drilling rod with a respective counter thread must be performed with extreme care and also by feeling, so that there is the risk that frequently the first thread turns are strained, squeezed, and deformed so that the drilling rod becomes unusable. This is true especially for the underground mining with its limited light condition.
Further, for exchange of the adaptor the whole clamping head must be dismounted, for example, when successively drilling must be performed with drilling rods of different types with different diameters and therefore different threads.
Another rock drilling machine is disclosed in the German reference DE-AS 28 12 096. This machine has a turnable carriage and a rotary drilling drive which moves along the carriage. The rotary drilling drive moves up and down by means of a rope winch as a displacement drive,along the carriage. The portion of the rope is fixed on one part and the rotary drilling drive is fixed on another part of a cylinder-piston unit. This cylinder-piston unit is provided between the engaging points of the displacement drive with pulling ropes and the carts of the rotary drilling drive. Correspondingly, with the identical downwardly directed drilling direction of this rock drilling machine, the cylinder-piston unit is formed as a single-acting and not suitable for horizontal drilling or for upwardly directed drilling. Moreover, this equalization system is suitable only for drilling machines in which the displacement drive is connected through ropes or chains with the rotary drilling drive.
Another disadvantage here is the high weight of the whole rotary drilling drive which for inserting a drilling rod must be also moved and can load the thread turns, and also the heaviness of the displacement device of the drilling machine for displacing the rotary drilling drive.